The overall objective of the proposed research is to understand neural mechanisms underlying auditory-vocal interaction and auditory feedback processing during hearing in the primate brain. Such mechanisms are important for vocal control and learning as well as hearing but are poorly understood. Few studies have investigated these neural mechanisms in non-human primates because of technical difficulties in studying the activity of individual neurons during natural vocal behaviors. We will use a unique model system, the common marmoset (Callithrix jacchus), to tackle these problems at the cellular and behavioral levels. The marmoset provides several important advantages over other non-human primate species: a rich vocal repertoire, a high reproductive rate while in captivity, and a smooth brain allowing easy access to all parts of the cerebral cortex. In this application, we will advance this line of research by addressing several fundamental questions on auditory-vocal interaction mechanisms using newly developed wireless neural recording and brain cooling techniques. A prominent property associated with self-produced speech or vocalization is the inhibition of neural activity in auditory cortex. In Aim 1, we will use feedbac perturbation techniques to study the dynamics of auditory-vocal interactions, both behaviorally and physiologically. In Aim 2, we will study the role of rostral and caudal auditory cortical pathways in auditory-vocal interactions. In Aim 3, we will determine the source of this vocalization-induced inhibition. Findings from the proposed study will shed lights on neural mechanisms responsible for vocal feedback processing in the primate brain and have implications for understanding how the auditory cortex operates during speaking and hearing.